The current world financial crisis that had everyone so worried? A mere wave, he said, in comparison to the tsunami that is on its way. And that tsunami? Human evolution.

Scientists are ‘rebooting’ human cells to perform different functions, he said, creating robotic body parts, bionic ears that will one day give super hearing, and bionic eyes that can zoom and see ultraviolet and infrared – so what does that mean for us?

According to Enriquez, it means the humble Homo sapiens will soon begin to develop into a whole new species. One with a new body that’s stronger, more sensitive and more capable than even the most blessed of natural human forms. A new species called ‘Homo evolutis’.

‘And this isn’t 1,000 years out,’ he said. ‘I think we’re going to glance at it during our lifetimes, and our grandchildren will begin to live it.’

Last year at the Beijing Olympics, Pistorius used these legs to come within 0.7 of a second of qualifying for the regular, able-bodied 400-metre event. And advancing technology means, Enriquez told his audience, that one day, regular human legs won’t be enough.

‘Next Olympics, you can bet that Oscar or one of his successors will make the time. And after that, they will be unbeatable.’

On the opposite side of the United States, on the wild, rocky coast of northern California, lives the man responsible for creating these remarkable carbon graphite ‘feet’, Van Phillips.

He has come down to a local beach for his regular run, and he has no idea that his invention is being taken as a portent of the end of the human race as we know it. ‘Really?’ he says, flashing an impressive set of white teeth. ‘Wow. I never heard about that.’

He considers the question of whether the feet could outperform regular legs. ‘I’m the inventor and I want to believe these legs can be faster,’ he says. ‘I guess they could. Even now, this foot is lighter and can store way more energy than a human foot.’ He shrugs, grinning again.

One glance at Van Phillips will tell you that his invention is a deeply personal one. His left leg was severed below the knee in a waterskiing accident when he was in university, and the prosthetic limb he wears today represents decades of hard work to find his way back from that injury.

‘On a good day,’ he says, ‘when there’s no pain and it’s fitting really well, then the leg performs kind of magically. It really does just perform like the other leg.’

To understand the revolution that his Flex Foot design represents, it’s worth looking back a couple of decades at what a prosthetic used to be like before Van and his carbon graphite hit the scene. The most that someone who lost a leg could count on was a straight length of wood or aluminium with a foam rubber ‘foot’ attached.

‘After the accident,’ Van says grimly, ‘I was fitted with a leg that felt like a fencepost with a bowling ball on the end of it. And god, if that wasn’t just the starkest, most brutal piece of reality. I could make it walk, but that’s all I could do. I couldn’t run on the beach. I couldn’t step off a kerb. I would hit a pebble no bigger than a dime and fall over it.
I hated it. I would throw it across the room.’

Well-meaning friends gave Van tough advice: he would just have to learn to live with it. But he knew instinctively that the basic leg design could be improved.

‘I just kept saying to myself, like a mantra: this is 1976. We’ve put man on the moon. And yet here I have this piece of crap. I knew, inside myself, that we could do a lot better.’

Van is finished with his run, and pauses for a moment to swap his ‘running foot’ for his ‘walking foot’ (he has any number of varieties, specially designed for all his activities, including feet for surfing and mountain climbing). So how did he go about reinventing the wheel?

‘I’d done karate, pole vaulting and springboard before the accident,’ he says, ‘and I had ideas on how that spring action might work to improve the leg. After some time [during which, Van later reveals, he went to an ashram in India and thought he might like to be a beekeeper], I learned prosthetics and got a job in a prosthetics lab. They told me my idea would probably never work, but they were happy for me to come in at the weekends to work on it.’

So began a process that lasted several years and around 300 different prototypes. Van created one prototype a week, and each week he would wear it and break it, and then the next week he would create a new one.

He experimented with different materials, and for inspiration on the shape, he looked to nature, studying the way animals run. Fittingly, it was nature’s fastest runner, the cheetah, which eventually provided the key.

‘I looked at the cheetah’s hind leg, with its long tendon extending in a C-shape from hip to foot,’ he says. ‘When the animal lands on the ground at 50 miles per hour, that long tendon is being stretched like a catapult. It’s the long tendon fibres that propel the animal forward. I figured, carbon graphite is twice as strong as steel, and can be flexible and release energy, so if we modelled the leg on that shape…’

The Cheetah Flex Foot was born. And it was a revolution for disabled people everywhere. When athlete Aimee Mullins became one of the first to receive the new Cheetah legs, she quickly gained iconic status and the attention of the world’s media.

According to Mullins, this marked a sea change in the way people perceived disability ‘and its historical “less than” status’.

Mullins also paved the way for athletes such as Pistorius (above right), to compete on level terms with able-bodied runners. And she thinks that things will progress still further. As she told Wired: ‘We may be pushing past Darwin’s vision of human evolution, where humans can become the architects of their own identities by designing the body to supersede the pace of nature’s adaptation.’

Van may have helped to change the lives of Mullins, Pistorius and many others, but he is reluctant to play the altruist. ‘I think it’s wonderful that there are people out there who are benefiting from my design,’ he says. ‘But I have to be honest and say I didn’t start this to make legs for other people. The only reason that it got done is because I really, really wanted it. There’s nothing I would have worked on that long if it weren’t for my benefit.’

Van leads the way into his stunning home, which is set amidst acres of rolling farmland on a grassy clifftop and surrounded on three sides by the churning Pacific Ocean. His living room is dominated by a desk overflowing with technical drawings of new designs, and when he reveals what they are for, it’s rather more difficult for him to claim a selfish agenda.

In 2000, Van sold his Flex Foot company, and with some money in his pocket, he set out to realise an even bigger dream. He aimed to create a foot that works well but that would be low-cost enough to distribute among the world’s most disadvantaged amputees – land mine victims.

Across the world, a person steps on a land mine every 19 minutes, leaving hundreds of thousands as leg amputees.

‘Their situation is 1,000 times worse than mine,’ Van says. ‘In Vietnam or Iraq, you may not even get fitted with a prosthetic limb, and if you do get one, it doesn’t function properly. Then, you’re living in a Third World country, being on your feet all day, working in rice paddies, building roads – it’s a nightmare.’

He’s worked on his ‘budget foot’ design for nine years, and while he suspects it will probably take another few years to develop, he’s determined to succeed. ‘I’ve easily spent over a million dollars on this project,’ he says. ‘And I really don’t care. My only concern is that I reach the result we’re looking for.’

And what of the future? ‘Ultimately it’s about not having prosthetics at all,’ Van says. ‘One day, it will be regenerated limbs. But before that, improvements can still be made. For example, I’d like to go and stand for hours in the Louvre. At the moment, that would be tough for me to do. In fact, it’s a problem that I’m working on right now…’

He smiles. Knowing Van, it’s not hard to suspect that one day he will get his wish – and then, at some point soon afterwards, perhaps he’ll be able to stand there for longer than everyone else, too.